Add rectangular window, put window normalizing into qt_window app

Author: Tony Kirke

qt_window/make_filter.cpp

@@ -93,11 +93,11 @@ double make_filter::update(double *w) {
   case Kaiser:		       taps = design_window("kaiser", kaiser_taps, kaiser_beta); break;
   case None:			for (int i = 0; i < pts; i++) w[i] = 1.0;			break;
   }
-	/*
-  std::cout << "Taps[] = {";
-  for (size_t i=0;i<taps.size();i++) std::cout << taps[i] << " ";
-  std::cout << "}\n";
-	*/
+	// Normalize for Frequency plots
+	float_type sum = 0;
+	for (size_t i=0;i<taps.size();i++) sum += taps[i];
+	for (size_t i=0;i<taps.size();i++) taps[i] /= sum;
+	
   fir_freq(taps, pts, w, 1.0);
   return (0);
 }

spuce/filters/design_window.h

@@ -24,13 +24,9 @@ std::vector<float_type> design_window(const std::string& fir_type, int order, fl
 	} else if (fir_type == "chebyshev") {
 		win = cheby(order, beta);
 	} else {
-		std::cout << "Invalid type " << fir_type << "\n";
+		win = rectangular(order);
 	}
 
-	// Normalize DC response to 1.0
-	float_type sum = 0;
-	for (size_t i=0;i<win.size();i++) sum += win[i];
-	for (size_t i=0;i<win.size();i++) win[i] /= sum;
 	return win;
 }
 }  // namespace spuce

spuce/filters/window.cpp

@@ -71,6 +71,11 @@ float_type io(float_type x) {
   }
   return (e);
 }
+std::vector<float_type> rectangular(long nf) {
+    std::vector<float_type> w(nf);
+    for (int i = 0; i < nf; i++) w[i] = 1.0;
+    return (w);
+}
 //!  \ingroup fir
 //! \brief hamming window \f$ w(n) = 0.54 - 0.46*cos( 2*\pi*n/(nf-1) )\f$
 std::vector<float_type> hamming(long nf) {

spuce/filters/window.h

@@ -6,34 +6,32 @@ namespace spuce {
 //! \file
 //! \brief Various FIR window functions: hamming,hanning,blackman,kaiser, chebyshev
 //
-//! \brief bessel function for kaiser window
-//! \author Tony Kirke
-//! \ingroup functions fir
-float_type io(float_type x);
+//! \brief rectangular window \f$ w(n) = 1;\f$
+//!  \ingroup functions fir
+std::vector<float_type> rectangular(long nf);
 //! \brief hamming window \f$ w(n) = 0.54 - 0.46*cos( 2*\pi*n/(nf-1) )\f$
-//! \author Tony Kirke
 //!  \ingroup functions fir
 std::vector<float_type> hamming(long nf);
 //! \brief hanning window \f$ w(n) = 0.5( 1 - cos( 2*\pi*n/(nf-1) )\f$
-//! \author Tony Kirke
 //!  \ingroup functions fir
 std::vector<float_type> hann(long nf);
+//!  \ingroup functions fir
 std::vector<float_type> hanning(long nf);
 //! \brief Blackman Window	\f$ w[x] = 0.42 - 0.5*cos(2*\pi*x/nf) + 0.08*cos(2*\pi*x/nf)\f$
-//! \author Tony Kirke
 //!  \ingroup functions fir
 std::vector<float_type> blackman(long nf);
 //! \brief kaiser window
-//! \author Tony Kirke
 //!  \ingroup functions fir
 std::vector<float_type> kaiser(long nf, float_type beta);
-//! \brief calculate beta for kaiser window for a given ripple
-float_type kaiser_beta(float_type beta);
 //!  \brief dolph chebyshev window design
-//! \author Tony Kirke
 //!  \ingroup functions fir
 std::vector<float_type> cheby(int nf, float_type alpha);
-//
 //! \brief bartlett window design
+//!  \ingroup functions fir
 std::vector<float_type> bartlett(long nf);
+//! \brief calculate beta for kaiser window for a given ripple
+float_type kaiser_beta(float_type beta);
+//! \brief bessel function for kaiser window
+float_type io(float_type x);
+
 }  // namespace spuce